/usr/include/ossim/elevation/ is in libossim-dev 1.8.16-4ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ossim/elevation/ossimDtedElevationDatabase.h
/usr/include/ossim/elevation/ossimDtedFactory.h
/usr/include/ossim/elevation/ossimDtedHandler.h
/usr/include/ossim/elevation/ossimElevCellHandler.h
/usr/include/ossim/elevation/ossimElevCellHandlerFactory.h
/usr/include/ossim/elevation/ossimElevLess.h
/usr/include/ossim/elevation/ossimElevManager.h
/usr/include/ossim/elevation/ossimElevSource.h
/usr/include/ossim/elevation/ossimElevSourceFactory.h
/usr/include/ossim/elevation/ossimElevationAccuracyInfo.h
/usr/include/ossim/elevation/ossimElevationDatabase.h
/usr/include/ossim/elevation/ossimElevationDatabaseFactory.h
/usr/include/ossim/elevation/ossimElevationDatabaseFactoryBase.h
/usr/include/ossim/elevation/ossimElevationDatabaseRegistry.h
/usr/include/ossim/elevation/ossimGeneralRasterElevFactory.h
/usr/include/ossim/elevation/ossimGeneralRasterElevHandler.h
/usr/include/ossim/elevation/ossimGeneralRasterElevationDatabase.h
/usr/include/ossim/elevation/ossimHgtRef.h
/usr/include/ossim/elevation/ossimImageElevationDatabase.h
/usr/include/ossim/elevation/ossimImageElevationHandler.h
/usr/include/ossim/elevation/ossimSrtmElevationDatabase.h
/usr/include/ossim/elevation/ossimSrtmFactory.h
/usr/include/ossim/elevation/ossimSrtmHandler.h
/usr/include/ossim/elevation/ossimTiledElevationDatabase.h